Function zapdir_to_glyph

src/display.c:2460–2470

* zapdir_to_glyph() * * Change the given zap direction and beam type into a glyph. Each beam * type has four glyphs, one for each of the symbols below. The order of * the zap symbols [0-3] as defined in defsym.h are: * * | S_vbeam ( 0, 1) or ( 0,-1) * - S_hbeam ( 1, 0) or (-1, 0) * \ S_lslant ( 1, 1) or (-1,-1) * / S_rslant (-1, 1) or ( 1,-1) *

 *      /  S_rslant     (-1, 1) or ( 1,-1)
 */
int
zapdir_to_glyph(int dx, int dy, int beam_type)
{
    if (beam_type >= NUM_ZAP) {
        impossible("zapdir_to_glyph:  illegal beam type");
        beam_type = 0;
    }
    dx = (dx == dy) ? 2 : (dx && dy) ? 3 : dx ? 1 : 0;

    return ((int) ((beam_type << 2) | dx)) + GLYPH_ZAP_OFF;
}

/*
 * Utility routine for dowhatis() used to find out the glyph displayed at